Typha domingensis energy-absorbing thin-walled composite structure

Abstract

The application discloses a kind of imitated carex buffer energy-absorbing thin-walled composite structures, including by a plurality of imitated carex crescent structure symmetrical combination and form bionic structure, imitated carex crescent structure includes outer arc plate, inner arc plate, the connecting flat plate for connecting the side of outer arc plate and inner arc plate and the several rib plates that are evenly distributed between outer arc plate and inner arc plate.The bionic structure of the application is combined by imitated carex crescent structure, is derived from the design of the internal characteristics of carex, and the whole bionic structure contains multiple levels of morphology and can effectively promote the bionic structure to disperse the impact energy to different structural levels when being subjected to axial impact, thereby buffering the impact force acting on the structure surface.The stress on the outside of the crescent is greater than the stress on the inside during the impact process, resulting in uneven stress on the crescent structure, effectively preventing structural instability and enhancing the impact resistance of the structure.Therefore, the whole bionic structure can effectively improve the carrying capacity and buffer energy-absorbing characteristics, ensuring a certain initial peak force and total energy absorption.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of buffering and energy absorption of large structures such as buildings, offshore platforms, and the buffering and energy absorption of vehicles such as ships, aerospace vehicles, automobiles, high-speed trains, etc. in the process of impact collision, and particularly relates to a cattail-imitating buffering and energy absorption thin-walled composite structure. BACKGROUND

[0002] At present, with the increase in the speed of daily vehicles, the threat of strong impact loads such as collisions is becoming more and more common. In the field of shipping, the main threat faced by ships is the collision impact in the event of a collision between two ships or grounding. In addition, marine structures such as offshore platforms and oil storage facilities are also prone to collision impacts from ships. Due to the harsh natural conditions at sea and the fact that marine structures are far from shore, it is difficult to timely deliver logistical support and energy supplies. Therefore, it is crucial to improve the impact resistance of ships and marine structures. In addition, when a car collides during high-speed driving, the severe impact will pose a serious threat to the safety of life and property of personnel. By improving the energy-absorbing crashworthiness of the car bumper and the car body structure, the impact damage to the human body and economic losses can be reduced.

[0003] Metal thin-walled energy-absorbing structures are a common protective structure, which are mostly made of traditional metal thin-walled tubes and their derivative structures. In traditional thin-walled energy-absorbing structures, corrugated thin-walled tube structures have the advantages of induced deformation, stable deformation, and lightweight structure, and can effectively dissipate the kinetic energy generated in impact collision through the plastic deformation of the metal itself, and thus are widely used in the collision energy dissipation structures of vehicles such as ships, cars, high-speed trains, and airplanes. However, the traditional corrugated tube has poor impact resistance and low energy absorption. Therefore, in order to further improve the energy-absorbing characteristics of the thin-walled structure, the performance is improved through structural optimization design and composite with other material structures.

[0004] Bionic structures are mainly based on biological structures in nature, and the characteristics of biological structures are introduced into thin-walled energy-absorbing structures, and then thin-walled structures with more excellent crashworthiness are designed. With the development of bionic engineering technology, bionic thin-walled energy-absorbing structures have been designed through various organisms, such as imitation of cow horn structure, imitation of shrimp claw structure, imitation of bamboo structure, imitation of horsetail structure, imitation of lotus leaf vein structure, etc. The cattail has a high slenderness ratio, and the complex internal fiber rib structure can effectively withstand environmental external loads such as gravity and wind, especially the impact resistance and crashworthiness. The cross section of the cattail is similar to a crescent shape, and contains a large number of voids, which are composed of multiple layers of fiber rib plates arranged in a regular manner. Therefore, the excellent performance of the cattail can be used for reference to design a bionic structure to improve the crashworthiness of the thin-walled structure.

[0005] The existing technical solution (CN114962511A) proposes a double-tube thin-wall energy-absorbing structure of shear thickening fluid, wherein the bending moment and stress at the corrugated part of the corrugated tube are larger when the corrugated tube is impacted, so that the corrugated tube can guide the structure to deform when the corrugated tube is impacted; the rigidity of the window tube along the area of the window is smaller due to the window, and the structure will also deform at the window; however, the platform in the energy-absorbing stage is short and unstable; the initial peak force decreases, but is still large, and the force is transmitted, and the protected structure has the risk of deforming and damaging first; and the total energy absorption of the structure in the scheme needs to be improved.

[0006] Therefore, the above problems need to be solved. SUMMARY

[0007] The purpose of the present application is to provide a reed-like buffer energy thin-wall composite structure which effectively improves the bearing capacity and buffer energy absorption characteristics.

[0008] Technical scheme: In order to achieve the above purpose, the present application discloses a reed-like buffer energy thin-wall composite structure, which comprises a bionic structure composed of a plurality of reed-like crescent structures symmetrically combined, the reed-like crescent structure comprising an outer arc plate, an inner arc plate, a connecting flat plate for connecting the side edges of the outer arc plate and the inner arc plate, and a plurality of rib plates uniformly distributed between the outer arc plate and the inner arc plate.

[0009] The outer arc surface of the outer arc plate has the parametric equation characteristics of r1θ1, r1 is the radius of the outer arc to determine the radius of the reed-like crescent structure, and θ1 is the outer arc angle to determine the outermost arc length of the reed-like crescent structure.

[0010] Preferably, the inner arc surface of the inner arc plate has the parametric equation characteristics of a-r2θ2, a determines the center position of the inner arc plate, r2 is the radius of the inner arc plate, a and r2 jointly determine the distance between the innermost side and the outermost side of the reed-like crescent structure, and θ2 is the inner arc angle to determine the innermost arc length of the reed-like crescent structure. Further, it also comprises a tapered corrugated conical tube coaxially arranged outside the bionic structure, an upper sealing cover for sealing the tapered corrugated conical tube and the upper end of the bionic structure, and a lower sealing cover for sealing the tapered corrugated conical tube and the lower end of the bionic structure.

[0011] Further, the trigonometric function curve of the tapered corrugated conical tube is:

[0012] R0 is the radius of the large opening of the tapered corrugated conical tube, k is the taper slope of the tapered corrugated conical tube, A is the amplitude of the tapered corrugated conical tube, L2 is the length of the tapered corrugated conical tube, and N is the number of corrugations of the tapered corrugated conical tube.

[0013] ​​Preferably, the cavity between the tapered tube with gradually changing corrugation and the bionic structure is filled with a shear thickening liquid or a shear thickening gel.

[0014] Further, the cavity in the bionic structure is filled with a shear thickening liquid or a shear thickening gel.

[0015] Further, the rib plate is a vertical rib plate, an inclined rib plate or an arc-shaped rib plate.

[0016] Preferably, the rib plate is provided with a plurality of windows arranged at intervals.

[0017] Further, the outer arc plate or the inner arc plate is provided with a plurality of windows arranged at intervals.

[0018] Advantages: Compared with the prior art, the present application has the following remarkable advantages:

[0019] (1) The bionic structure of the present application is composed of two crescent structures derived from the internal characteristics of cattail, and the bionic structure comprises a hollow tubular shape and a crescent shape. These multi-level shapes can effectively disperse the impact energy to different structural levels when the bionic structure is subjected to axial impact, thereby buffering the impact force acting on the surface of the structure. During the axial impact process, the outer side of the crescent structure is subjected to greater stress than the inner side, making the structure unevenly stressed and prone to instability, resulting in insufficient deformation of the structure. Therefore, the two crescent structures are symmetrically combined to form the bionic structure in the present application, thereby effectively preventing the structure from being unstable, promoting complete deformation and improving the impact resistance of the structure. At the same time, the rib plate provided in the structure can increase the strength of the structure and guide the ordered deformation of the structure, thereby promoting sufficient deformation of the structure. In addition, the stress at the windowed part is greater than that at the non-windowed part, so that the local structure deforms first, thereby reducing the initial peak force of the structure during impact. Therefore, the bionic structure can effectively improve the energy absorption characteristics and ensure that it has a lower initial peak force and a higher total energy absorption.

[0020] (2) The gradually changing corrugated conical tube in the application is a special corrugated tube. Compared with the traditional corrugated tube, the corrugation of the gradually changing corrugated conical tube is arranged in a conical shape, and the shape and depth gradually change with the change of the length, so that the flexibility and elasticity performance also change. When the gradually changing corrugated conical tube is subjected to axial impact, the energy absorption and buffering are divided into two parts. One part is the elastic deformation of the corrugation, which converts part of the impact energy into elastic potential energy, thereby buffering and absorbing the impact force. The other part is the plastic deformation of the corrugation, thereby absorbing a large amount of impact energy. The structure of the gradually changing corrugated conical tube is conical, which can be equivalent to: the inside is composed of multiple corrugated cylindrical structures stacked layer by layer, and the cylinders are connected through gradually changing angles and radii. Since the gradually changing corrugated conical tube is conical, it will deform plastically under impact load and form a plastic hinge. The plastic hinge causes irreversible deformation of the structure through stretching and rotation, thereby absorbing a large amount of impact energy. At the same time, by changing the shape and depth of the corrugation, the gradually changing corrugated conical tube realizes uniform stress distribution and step-by-step energy dissipation. During the axial impact process, since the corrugation of the gradually changing corrugated conical tube gradually changes from deep wave to shallow wave, the degree of plastic deformation of each layer of corrugation guide structure is different, and the entire energy absorption process presents a slow and step-by-step rising. Such energy absorption characteristics realize the effect of dispersing impact force layer by layer, thereby effectively absorbing and buffering impact energy and reducing the impact on the protected object.

[0021] (3) The gradually changing corrugated conical tube is set as an outer tube, the bionic structure is set as an inner tube, and the two structures are placed vertically and coaxially to form a bionic composite structure. When the bionic composite structure is impacted, the symmetrical crescent shape of the bionic structure and the characteristics of the built-in window ribbed plate make it have a certain stiffness, and the gradually changing corrugated conical tube has a conical shape, so the internal radius and angle gradually change with the depth, resulting in a gradual energy absorption characteristic. When the bionic composite structure is subjected to axial impact, the corrugation of the outer tube deforms from deep wave to shallow wave layer by layer from top to bottom, and the deformation is neat and smooth. Compared with the bionic structure alone, the instability of the built-in inner tube is obviously improved, the axial deformation of the entire structure is stable and sufficient, and the energy absorption platform is stable. Therefore, the bionic composite structure has low initial peak force and high energy absorption characteristics, which can effectively reduce the damage to the protected structure and personnel in practical applications.

[0022] (4) The present application fills the inner tube of the bionic composite structure with shear thickening fluid; the viscosity of the shear thickening fluid changes with the change of the shear rate, when the shear rate reaches a certain range, the shear thickening fluid appears "shear thickening" phenomenon, and has the characteristics of "strong when strong"; when the bionic composite structure filled with shear thickening fluid is impacted, a large amount of energy can be absorbed, part of the energy is consumed by the plastic deformation of the structure itself, another part is absorbed by the shear thickening fluid due to the change of the shear thickening form from "liquid state" to "solid state", and the shear thickening shear thickening fluid can induce secondary deformation of the part of the structure that has not been completely deformed, thereby further improving the total energy absorption of the whole structure. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the composite structure in the present application;

[0024] Figure 2 It is a schematic diagram of the cattail moon structure in the present application;

[0025] Figure 3 It is a schematic diagram of the bionic structure in the present application;

[0026] Figure 4 It is a structural schematic diagram of the tapered corrugated pipe in the present application;

[0027] Figure 5 It is a structural schematic diagram of the upper cover in the present application;

[0028] Figure 6 It is a structural schematic diagram of the lower cover in the present application;

[0029] Figure 7 It is a schematic diagram of the cattail moon structure with different forms of ribbed plates in the present application;

[0030] Figure 8 It is a schematic diagram of the cattail moon structure with different window positions in the present application;

[0031] Figure 9 It is a schematic diagram of the bionic structure composed of several cattail moon structures in the present application;

[0032] Figure 10 It is a deformation diagram of the bionic structure in the present application;

[0033] Figure 11 It is a deformation diagram of the tapered corrugated pipe in the present application;

[0034] Figure 12 It is a deformation diagram of the bionic composite structure in the present application;

[0035] Figure 13 It is a deformation diagram of the bionic structure in the present application, and the cavity is filled with shear thickening fluid;

[0036] Figure 14 The force-displacement curves of different bionic structures and corrugated / window structures are compared.

[0037] Figure 15 The force-displacement curves of different bionic composite structures and corrugated / window structures are compared. DETAILED DESCRIPTION

[0038] The technical solutions of the present application are further described below with reference to the accompanying drawings.

[0039] As shown in Figure 1 , the present application discloses a cattail-like buffer energy-absorbing thin-walled composite structure, which comprises a bionic structure 6 composed of a plurality of cattail-like crescent structures 1, as shown in Figure 2 , the cattail-like crescent structure 6 comprises an outer arc plate 7, an inner arc plate 8, a connecting flat plate 9 for connecting the side edges of the outer arc plate and the inner arc plate, and a plurality of rib plates 10 evenly distributed between the outer arc plate and the inner arc plate. The rib plate 10 is a vertical rib plate, an inclined rib plate or an arc-shaped rib plate. A plurality of windows are arranged at intervals on the rib plate 10. A plurality of windows are arranged at intervals on the outer arc plate 7 or the inner arc plate 8.

[0040] The outer arc surface of the outer arc plate 7 has characteristics of a parametric equation, r1 is the radius of the outer arc plate 7, which determines the radius of the cattail-like crescent structure 1, and θ1 is the outer arc angle of the outer arc plate 7, which determines the outermost arc length of the cattail-like crescent structure 1.

[0041] The inner arc surface of the inner arc plate 8 has characteristics of a parametric equation, a determines the center position of the inner arc plate 8, r2 is the radius of the inner arc plate 8, a and r2 together determine the distance between the innermost and outermost sides of the cattail-like crescent structure 1, and θ2 is the inner arc angle, which determines the innermost arc length of the cattail-like crescent structure 1.

[0042] It also includes a tapered corrugated conical tube 2 coaxially arranged outside the bionic structure 6, an upper cover 3 for sealing the upper end of the tapered corrugated conical tube 2 and the bionic structure 6, and a lower cover 4 for sealing the lower end of the tapered corrugated conical tube 2 and the bionic structure 6. The trigonometric function curve of the tapered corrugated conical tube 2 is: R0 is the radius of the large end of the tapered corrugated conical tube 2, k is the taper slope of the tapered corrugated conical tube 2, A is the amplitude of the tapered corrugated conical tube 2, L2 is the length of the tapered corrugated conical tube 2, and N is the number of corrugations of the tapered corrugated conical tube 2. The cavity between the tapered corrugated conical tube 2 and the bionic structure 6 is filled with a shear thickening liquid or a shear thickening gel. The cavity in the bionic structure 6 is filled with a shear thickening liquid 5 or a shear thickening gel.

[0043] The material of the imitation cattail crescent structure 1, the gradually changing corrugated conical pipe 2, the upper cover 3 and the lower cover 4 is selected from stainless steel or Q235 or other metal or new polymer material with good plasticity and toughness.

[0044] As shown in Figure 2 , the imitation cattail crescent structure 1 comprises an outer arc plate 7, an inner arc plate 8, a connecting flat plate 9 for connecting the side edges of the outer arc plate and the inner arc plate, and a plurality of rib plates 10 evenly distributed between the outer arc plate and the inner arc plate. The outer arc surface of the outer arc plate 7 has the parametric equation characteristics of r1cosθ1, wherein r1 is the radius of the outer arc plate 7, and θ1 is the outer arc angle, which determines the outermost arc length of the imitation cattail crescent structure 1. The inner arc surface of the inner arc plate 8 has the parametric equation characteristics of a-r2cosθ2, wherein a is the center position of the inner arc plate 8, r2 is the radius of the inner arc plate 8, a and r2 jointly determine the distance between the innermost side and the outermost side of the imitation cattail crescent structure 1, and θ2 is the inner arc angle, which determines the innermost arc length of the imitation cattail crescent structure 1. The length and width of the connecting flat plate 9 for connecting the side edges of the outer arc plate and the inner arc plate need to match the outer arc plate 8 and the inner arc plate 9.

[0045] As shown in Figure 3 and Figure 9 , the bionic structure 6 in the application is composed of two imitation cattail crescent structures 1, and the bionic structure 6 can also be composed of a plurality of imitation cattail crescent structures 1.

[0046] As shown in Figure 4 , the trigonometric function curve of the gradually changing corrugated conical pipe 2 is: R0 is the radius of the large opening of the gradually changing corrugated conical pipe 2, k is the conical slope of the gradually changing corrugated conical pipe 2, A is the amplitude of the gradually changing corrugated conical pipe 2, L2 is the length of the gradually changing corrugated conical pipe 2, and N is the number of corrugations of the gradually changing corrugated conical pipe 2.

[0047] In terms of processing technology, the production and manufacturing process of the bionic structure, the gradually changing corrugated conical pipe and the upper and lower covers used in the application is as follows:

[0048] (1) Processing of the bionic structure: the bionic structure used in the application has a complex inner cavity structure, and can be processed by adopting the mode of sand core combination integral casting.

[0049] (2) The processing of the tapered corrugated pipe: the tapered corrugated pipe used in the application is made by the method of hydraulic bulging of a thin-walled pipe in a mold, wherein the mold can be repeatedly used for many times;

[0050] (3) The processing of the upper and lower covers: the upper and lower covers used in the application are processed by the method of laser cutting according to the actual shape and size, and the whole processing is easy to realize, as shown in Figs. Figure 5 and Figure 6 ;

[0051] The main buffer energy-absorbing part of the cattail-imitated buffer energy-absorbing thin-walled composite structure is the bionic structure 6, the tapered corrugated pipe 2 and the shear thickening liquid 5. The symmetrical crescent shape and the feature of the built-in window rib plate of the bionic structure can improve the strength and stiffness of the whole structure, and the tapered corrugated pipe is tapered, and the internal radius and angle gradually change with the depth, so that the whole energy absorption is also gradual. When subjected to an axial impact load, the bionic structure and the tapered corrugated pipe in the cattail-imitated buffer energy-absorbing thin-walled composite structure deform plastically first; with the increase of the impact rate, the shear thickening liquid changes from "liquid" to "solid", and the "shear thickening" phenomenon appears; the solidified shear thickening liquid can fully deform the part of the bionic structure that has not been completely deformed, and further improve the total energy absorption of the whole structure.

[0052] When the cattail-imitated buffer energy-absorbing thin-walled composite structure is impacted, the whole structure deforms gradually and shrinks, the total energy absorption is large under a relatively low initial peak force, and the whole energy absorption platform is stable.

[0053] The present application is based on a cattail designed cattail-imitating buffer energy-absorbing thin-walled composite structure, which contains a bionic structure, a gradually changing corrugated conical tube structure and a shear thickening liquid filled in the bionic structure. The bionic structure is composed of two cattail-imitating crescent structures, which are derived from the internal characteristics of cattail and designed by the gap compartment structure of cattail to form a crescent cell structure with built-in windowed ribbed plate. The entire bionic structure contains hollow tubular morphology, crescent morphology and other multi-level morphologies, which can effectively promote the bionic structure to disperse the impact energy to different structural levels when subjected to axial impact, thereby buffering the impact force acting on the surface of the structure. During the axial impact process, the outer side of the cattail-imitating crescent structure is subjected to greater stress than the inner side, making the structure unevenly stressed and prone to instability, resulting in insufficient deformation of the structure. Therefore, the two cattail-imitating crescent structures are symmetrically combined to form a bionic structure in the present application, thereby effectively preventing structural instability, promoting complete deformation and improving the impact resistance of the structure. At the same time, the windowed ribbed plate arranged inside the structure can increase the structural strength and guide the ordered deformation of the structure, promoting sufficient deformation of the structure. In addition, the stress at the windowed part is greater than that at the non-windowed part, causing the local structure to deform first, thereby reducing the initial peak force of the structure during impact. Therefore, the entire bionic structure can effectively improve the buffer energy-absorbing characteristics and ensure a lower initial peak force and higher total energy absorption.

[0054] Example 1

[0055] As shown in Figure 7 , Example 1 is a bionic structure 6 composed of two cattail-imitating crescent structures 1. The material of the cattail-imitating crescent structure 1 is 304 stainless steel.

[0056] The radius r1 of the outer arc plate 7 of the cattail-imitating crescent structure 1 is 10 mm, and the outer arc angle is The circular position a of the inner arc plate 8 of the cattail-imitating crescent structure 1 is 6 mm, the radius r2 of the inner arc plate 8 is 10 mm, and the inner arc angle is The number i of the ribbed plate 10 arranged between the inner arc plate and the outer arc plate in the cattail-imitating crescent structure 1 is 3, and the angle between adjacent ribbed plates is The length and width of the connecting flat plate 9 for connecting the side edges of the outer arc plate and the inner arc plate in the cattail-imitating crescent structure 1 need to match the outer arc plate 8 and the inner arc plate 9. The thickness t1 of the outer arc plate 7, the inner arc plate 8, the connecting flat plate 9 and the ribbed plate 10 is 1 mm. The length L1 of the cattail-imitating crescent structure 1 is 60 mm. The material of the cattail-imitating crescent structure is 304 stainless steel.

[0057] The ribbed plates of the cattail-imitating crescent structure in the bionic structure 6 in Example 1 are vertical ribbed plates, inclined ribbed plates and arc ribbed plates, respectively, and the structural schematic diagram is as shown in Figure 7The radius of the rubber hose used for sealing the windows on the window tube is 8 mm; the radius of the upper and lower cover of the corrugation / window structure is 22.5 mm. The materials of the corrugation tube, the window tube and the upper and lower cover are all 304 stainless steel, and the material of the rubber hose is rubber. 2 The radius of the rubber hose used for sealing the windows on the window tube is 8 mm; the radius of the upper and lower cover of the corrugation / window structure is 22.5 mm. The materials of the corrugation tube, the window tube and the upper and lower cover are all 304 stainless steel, and the material of the rubber hose is rubber.

[0058] The mass of the impact object is 200 kg, and the impact speed is 15 m / s. The energy absorption, specific energy absorption, initial impact peak load and specific total efficiency of the corrugation / window thin-walled energy absorption structure and three different rib plate forms of the bionic structure in the prior art when subjected to axial collapse are shown in Table 1, and the impact force-displacement curve is shown in Figure 14

[0059] Table 1

[0060]

[0061] From the data in Table 1, the arrangement order of the specific energy absorption of the four structures is: bionic structure-rib plate inclined > bionic structure-rib plate vertical > bionic structure-arc rib plate > corrugation / window thin-walled energy absorption structure; the arrangement order of the specific total efficiency is: bionic structure-rib plate inclined > bionic structure-rib plate vertical > bionic structure-arc rib plate > corrugation / window thin-walled energy absorption structure; the arrangement order of the initial impact peak load is: bionic structure-arc rib plate < bionic structure-rib plate vertical < bionic structure-rib plate inclined < corrugation / window thin-walled structure; in summary, under the same impact conditions, the specific energy absorption and the specific total efficiency of the three different rib plate forms of the bionic structure in Example 1 are higher than those of the corrugation / window thin-walled energy absorption structure, so the energy absorption characteristics of the structure of the present application have obvious advantages compared with the corrugation / window thin-walled structure; and the initial impact peak load of the three different rib plate forms of the bionic structure in Example 1 is lower than that of the corrugation / window thin-walled structure, and the initial impact peak load of the three different rib plate forms of the bionic structure is basically unchanged, which can effectively protect the structure to be protected; in summary, the structure of Example 1 can be used in structures that need to withstand high energy during impact, but the structure is prone to "instability" due to the high aspect ratio, and the deformation mode during the entire energy absorption process is not very stable.

[0062] Example 2

[0063] As Figure 8 ​As shown, Example 2 is based on the study of the ribbed vertical biomimetic structure in Example 1, and a plurality of rectangular windows are arranged on the surface of the biomimetic structure at different positions in the circumferential direction; five different windowing positions are discussed, wherein the number of rectangular windows corresponding to the windowing on the ribbed biomimetic structure is 3, the number of windows in each column is 3, and the area of each window is 20.1 mm 2 ; the number of rectangular windows corresponding to the windowing on the outside of the biomimetic structure is 3, the number of windows in each column is 3, and the area of each window is 34.7 mm 2 ; the number of rectangular windows corresponding to the windowing on the inside of the biomimetic structure is 4, the number of windows in each column is 3, and the area of each window is 15.1 mm 2 or 25.3 mm 2 . The energy absorption parameters of the structure are shown in Table 2, the deformation diagram is shown in Figure 10 , and the impact force-displacement curve is shown in Figure 14 .

[0064] Table 2

[0065]

[0066] The difference in energy absorption between Example 2 and Example 1 is that the initial impact peak load is lower than that of the structure in Example 1, but the total energy absorption and specific energy absorption are still much higher than those of the corrugated / window thin-walled structure; the impact force-displacement curve is shown in Figure 14 It can be seen that the window has the functions of guiding plastic deformation and making the structure deform fully, and the stress in the window part is large, so the local deformation occurs first, thereby reducing the initial impact peak load; in addition, the window can alleviate the "buckling" phenomenon and promote the structure to deform fully. In Example 2, the biomimetic structure with only the ribbed window has no significant fluctuation in energy absorption, specific energy absorption, and initial peak force compared with Example 1, while the biomimetic structure with different windowing positions has slightly lower energy absorption and specific energy absorption than Example 1, but effectively reduces the initial peak force. As shown in the deformation diagram Figure 10 , the deformation mode of the biomimetic structure with only the ribbed window is the most stable, and there is no obvious "buckling" phenomenon; while the "buckling" phenomenon of the biomimetic structure with different windowing positions is also obviously improved compared with Example 1, and the entire Example 2 can effectively alleviate the "buckling" phenomenon and promote the structure to deform fully. Therefore, the structure of Example 2 can be used for structures that require a low initial peak force and relatively stable deformation in the impact process.

[0067] Example 3

[0068] Example 3 is a tapered corrugated tube with a radius R0 = 21.5 mm at the large end of the tapered corrugated tube 2, a tapering slope k = -0.125 of the tapered corrugated tube 2, an amplitude A = 1 of the tapered corrugated tube 2, a length L2 = 60 mm of the tapered corrugated tube 2, and a number of corrugations N = 6 of the tapered corrugated tube 2. The energy absorption parameters of the structure are shown in Table 3, and the corresponding deformation diagram is shown in Figure 11 The impact force-displacement curve is shown in Figure 15 .

[0069] Table 3

[0070]

[0071] The specific energy absorption of the tapered corrugated tube in Example 3 is slightly lower than that of the corrugated / window thin-walled structure, but the initial collision peak load of the tapered corrugated tube is effectively reduced, and the specific total efficiency is also much higher than that of the corrugated / window thin-walled structure. From Figure 11 the deformation diagram and Figure 15 the force-displacement curve diagram, it can be seen that when the tapered corrugated tube is subjected to axial impact, the corrugated plastic deformation gradually changes from deep to shallow, so the degree of plastic deformation of each layer of corrugated guide structure is different, and the entire energy absorption process presents a lasting and slow step-by-step rising; the deformation diagram shows the accordion deformation mode of the tapered corrugated tube, and the entire deformation process is very coordinated, which highlights the excellent performance of the tapered corrugated tube. The tapered corrugated tube can be applied in application scenarios where low load is required in the initial contact and step-by-step increasing load is required later.

[0072] Example 4

[0073] Example 4 is a bionic composite structure composed of the structures of Example 2 and Example 3. The bionic structure has certain stiffness and strength characteristics, but is prone to "instability phenomenon"; the tapered corrugated tube deforms stably and has certain elasticity and flexibility characteristics, but the "total energy absorption" is a bit weak; by combining the two structures, the stability of deformation can be improved, and the structure can also have certain good energy absorption characteristics. The energy absorption parameters of the structure are shown in Table 4, and the corresponding deformation diagram is shown in Figure 12 , and the impact force-displacement curve is shown in Figure 15 .

[0074] Table 4

[0075]

[0076] The energy absorption characteristics of the bionic composite structure are obviously higher than those of the corrugated / window thin-walled structure; when subjected to axial impact, the deformation mode of the bionic composite structure presents a mixed deformation mode of accordion and diamond, which is relatively stable; from Figure 15It can be seen that in the early and middle stages of impact, the energy absorption platform of the bionic composite structure is basically stable and tends to be horizontal; in the late stage of impact, the impact load of the bionic composite structure will have a large platform fluctuation rising, and the impact load of the bionic composite structure will have a large platform fluctuation rising, from Figure 12 It can be seen that the bionic composite structure is stable in the whole energy absorption process, and there is no "instability" phenomenon, and the deformation mode is similar to "accordion type". The combination of embodiment 2 and embodiment 3 obtains embodiment 4, which on the one hand ensures that the bionic composite structure has a certain energy absorption capacity, and on the other hand maintains the stability of the initial peak load within a certain range. The structure effectively relieves the impact energy of the protected object, thereby greatly protecting the safety of the protected object and the human body.

[0077] Embodiment 5

[0078] The structure of embodiment 4 is used to fill the cavity of the bionic structure with shear thickening liquid. Through the "shear thickening property" of shear thickening, the part of the bionic composite structure that has not been deformed can be fully deformed, thereby further improving the total energy absorption and energy absorption characteristics of the structure. The energy absorption parameters of the structure are shown in Table 5, and the corresponding deformation diagram is shown in Figure 13 , and the impact force-displacement curve is shown in Figure 15 .

[0079] Table 5

[0080]

[0081] The total energy absorption, specific energy absorption and specific total efficiency of the bionic composite structure filled with shear thickening liquid are higher than those of the corrugated / window thin-walled structure, and have certain energy absorption characteristics. Compared with the bionic composite structure of embodiment 4, the total energy absorption of the bionic composite structure filled with shear thickening liquid of embodiment 5 is significantly improved, and this structure can be used in scenarios that require higher energy absorption.

[0082] Embodiment 6

[0083] The structure of embodiment 1 or embodiment 2 or embodiment 3 or embodiment 4 is used to fill the cavity of the structure with energy absorption material. The filling position and filling amount of the energy absorption material can be referred to the actual application scenario, and the energy absorption material can be shear thickening liquid, shear thickening gel, rubber, etc. In order to further strengthen the energy absorption and specific energy absorption of the structure, the materials of the bionic structure, the tapered corrugated tube, the upper cover and the lower cover are replaced with new polymer materials.

[0084] The preferred embodiments of the present application are described in detail above, but the design concept of the present application is not limited thereto. Within the technical concept of the present application, various equivalent transformations of the technical solutions of the present application can be made, and these equivalent transformations all belong to the protection scope of the present application.

Claims

1. A cattail cushioning energy absorbing thin walled composite structure characterized by: The bionic structure (6) comprises a plurality of symmetrical cattail crescent structures (1), the cattail crescent structure (1) comprises an outer arc plate (7), an inner arc plate (8), a connecting flat plate (9) for connecting the side edges of the outer arc plate and the inner arc plate, and a plurality of rib plates (10) evenly distributed between the outer arc plate and the inner arc plate; the outer arc surface of the outer arc plate has the parametric equation characteristics of r1 is the radius of the outer arc plate, θ1 is the outer arc angle, and the outer arc angle determines the outermost arc length of the cattail crescent structure (1).

2. The cattail buffered energy absorbing thin-walled composite structure of claim 1, wherein: The inner arc surface of the inner arc plate has The parameter equation characteristics of a, r2, θ2, a and r2 jointly determine the distance between the innermost side and the outermost side of the cattail moon structure (1), and θ2 is the inner arc angle which determines the innermost arc length of the cattail moon structure (1).

3. The cattail buffered energy absorbing thin-walled composite structure of claim 1, wherein: A gradually-changing corrugated conical tube (2) coaxially sleeved outside the bionic structure (6), an upper cover (3) for sealing the upper end of the gradually-changing corrugated conical tube (2) and the bionic structure (6), and a lower cover (4) for sealing the lower end of the gradually-changing corrugated conical tube (2) and the bionic structure (6) are further included.

4. The cattail buffered energy absorbing thin-walled composite structure of claim 3, wherein: The trigonometric function curve of the tapered corrugated pipe (2) is: R0 is the radius of the large end of the tapered corrugated pipe (2), k is the tapering slope of the tapered corrugated pipe (2), A is the amplitude of the tapered corrugated pipe (2), L2 is the length of the tapered corrugated pipe (2), and N is the number of corrugations of the tapered corrugated pipe (2).

5. The cattail buffered energy absorbing thin-walled composite structure of claim 3, wherein: The cavity between the gradually-changing corrugated conical tube (2) and the bionic structure (6) is filled with a shear thickening liquid or a shear thickening gel.

6. The cattail buffered energy absorbing thin-walled composite structure of claim 1, wherein: The cavity in the bionic structure (6) is filled with a shear thickening liquid (5) or a shear thickening gel.

7. The cattail buffered energy absorbing thin-walled composite structure of claim 1, wherein: The rib plate (10) is a vertical rib plate, an inclined rib plate or an arc-shaped rib plate.

8. The cattail buffered energy absorbing thin-walled composite structure of claim 1, wherein: A plurality of windows are arranged on the rib plate (10) in an interval.

9. The cattail buffered energy absorbing thin walled composite structure of claim 1, wherein: A plurality of windows are arranged on the outer arc plate (7) or the inner arc plate (8) in an interval.

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